| 摘要 |
PURPOSE:To obtain the driving voltage pulse featuring an ample amplitude by eliminating the effect of the back-gate voltage in the voltage selection circuit. CONSTITUTION:When control signal terminal E features GND, FETQ22 and Q32 conduct. And -VDD is transmitted to output terminal H. Furthermore, control terminal F features -VDD, and thus FETQ12 conducts to transmit -1/3VDD to output terminal G. At the same time, -VDD is supplied to the back electrode of FETQ21 since FETQ32 is connected. Then in case terminal E is -VDD, FETQ11 conducts to send the GND voltage to terminal G. Then terminal F features the GND voltage, and thus FETQ21 and Q31 conduct. Here the potential of back-gate electrode of FETQ21 features nearly -2/3VDD by FETQ31. Accordingly, the back- gate bias can be ignored substantially between the back-gate electrode and the source electrode of FETQ21, and thus the voltage of output terminal HK-2/3VDD can be transmitted. |
